The unwanted loosening of orthopaedic implants of all types, including prosthodontic implants, is emerging as an enormous clinical problem in the United States and worldwide. In the United States alone, between 200,000 and 300,000 orthopaedic and prosthodontic implant procedures are performed annually, and it is anticipated that these numbers will continue to increase over time. It is estimated that after a service life of 10 or more years, approximately 10% of these implants will become loose due to periprosthetic bone resorption.
Unwanted bone loss also occurs in response to other conditions including but not limited to bone tumors and inflammatory arthritis. Clinical problems of various etiologies thus include not only the loosening of total joint arthroplasties and dental implants but also periarticular bone loss in inflammatory arthritis and pathologic fractures from carcinoma which is metastatic to bone or primary bone tumors such as Ewing's sarcoma or lymphoma (also generally known as round cell tumors). Bone resorption is thus a much more widespread affliction than may be evident from prosthesis-loosening statistics alone.
Surgical correction of undesirable bone resorption will never constitute an ideal treatment for bone loss, in part because surgery is generally the most invasive and traumatic solution to any medical condition and, more importantly, because it is only reactive and cannot be used preventively. The ideal solution to unwanted bone resorption would be a pharmacologically active approach wherein one or more active agents could be delivered to the area of bone resorption to halt and/or to prevent it. A need thus exists for a method of treating and/or preventing bone loss by means of methods and compositions for the pharmacologic inhibition of bone resorption.